Minimizing scouring action in water flow channels

ABSTRACT

A MEANS FOR MINIMISING THE SCOURING EFFECT OF WATER FLOW ON THE BEDS OF RIVERS, ESTUARIES AND THE SEA BED COMPRISING A TUBULAR ELEMENT COMPOSED OF A MESHED UPPER PANEL THROUGH WHICH BALLAST MATERIAL CAN PASS TO THE RIOR OF THE ELEMENT. IF DESIRED, THE ELEMENT MAY HAVE A MESHED LOWER PANEL THROUGH WHICH SAND OR OTHER BED MATERIAL MAY PASS BUT THROUGH WHICH THE BALLAST IS UNABLE TO ESCAPE AND A PLURALITY OF ELEMENTS MAY BE JOINED TOGETHER IN PARALLEL RELATIONSHIP TO FORM A UNIT. THE OR EACH TUBULAR ELEMENT MAY BE PROVIDED INTERNALLY WITH A PLURALITY OF SPACED APART DISTENDING MEMBERS.

FBTiG, I971 STAMMERS I 3,563,031

MINIMIZING SCOURING ACTION IN WATER FLOW CHANNELS Filed Dec. 17, 1968 V2 Sheets-Sheet 1 Feb. 16, 1971 J, T M RS 3,563,037

MINIMIZING SCOURING ACTION IN WATER FLOW CHANNELS Filed Dec. 17, 1968 2Sheets-Sheet 2 //WE/Y 722g )4LBEIET J. ST/MMHERS United States Patent3,563,037 MINIMKZING SCOURING ACTION IN WATER FLOW CHANNELS Albert JamesStammers, 23 Shottfield Ave., East Sheen, London, SW. 14, England FiledDec. 17, 1968, Ser. No. 784,314 Claims priority, application GreatBritain, July 18, 1968,

Int. Cl. E021) 3/04, 3/12 US. Cl. 613 9 Claims ABSTRACT OF THEDISCLOSURE A means for minimising the scouring effect of Water flow onthe beds of rivers, estuaries and the sea bed comprising a tubularelement composed of a meshed upper panel through which ballast materialcan pass to the interior of the element. If desired, the element mayhave a meshed lower panel through which sand or other bed material maypass but through which the ballast is unable to escape and a pluralityof elements may be joined together in parallel relationship to form aunit.

The or each tubular element may be provided internally with a pluralityof spaced apart distending members.

CROSS REFERENCES TO RELATED APPLICATIONS United Kingdom applicationsNos:12,429/65 dated Mar. 24, 1965 and 34,252/68 dated July 18, 1968.

BACKGROUND OF THE INVENTION This invention relates to an improved meansfor minimising the scouring effect of water flow on the beds and banksof water channels such as rivers, estuaries and the sea.

Heretofore, among the methods used to minimise this scouring action inwater flow channels, mattresses composed of bundles of willow and reedhave been constructed in the form of rafts which are floated to theparticular site and sunk by means of pieces of rock placed upon them byhand from an accompanying barge. This method has disadvantages in thatthe willow and reed have to be cut at a certain period, they are bulkyto transport, and the rocks, unless available on the site, also have tobe transported, the rafts can only be placed in position in certaintidal conditions, and when in position are liable to be undercut byscour, so that the raft is liable to tilt and allow the rocks to bedisplaced.

An object of the invention is to provide an improved means forminimising scouring of water flow channels which avoids the abovedisadvantages.

SUMMARY OF THE INVENTION According to the invention, there is providedmeans for minimising the scouring action in water flow channelscomprising a tubular element composed of a meshed upper panel throughwhich ballast material can pass to the interior of the element.

According to a feature of the invention the element is constructed fromrot-proof flexible material. It may be associated with a supportingframing and it may have a meshed lower panel through which sand or otherbed material may pass but through which the ballast is unable to escape.

According to a further feature of the invention a plurality of elementsmay be joined together in parallel relationship to form a unit.

According to a still further feature of the invention, the or eachtubular element is provided internally with a plurality of spaced apartdistending members. The dis- 3,563,037 Patented Feb. 16, 1971 tendingmembers may be of spherical, ovoid or other shape and may be providedwith irregular cavities. The distending members in each section may bethreaded on a wire with tubular spacing pieces between the members.

The distending members may be partially or fully filled with concrete orother heavy material so that they will assist in causing the element tosink when it is released.

According to another feature of the invention there is provided a methodof minimising scouring action in water flow channels which comprisesfloating one or a plurality of the said elements or units into positionin relation to the desired ultimate location, pouring or projectingballast thereon so that this enters the interior and causes the element,elements or units to sink to the ultimate location, and continuing withthe pouring of projecting of the ballast over the sunken element,elements or units to complete the filling thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of amattress-like unit constructed in accordance with the invention andhaving eight elements joined together;

FIG. 2 is a section on the line IIII of FIG. 1;

FIG. 3 is a transverse section through one of the compartments formedinside an element on a large scale;

FIG. 4 is a longitudinal section through a part of an elementconstructed according to a second embodiment of the invention; and

FIG. 5 is a transverse section through a part of an element which is amodification of the element shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 3 ofthe drawings, a mattresslike unit indicated generally by reference 1, isformed by two co-extensive sheets of rot-proof material such aspolyester fibre, for example that sold under the trademark Terylene. Thesuperimposed sheets are stitched or otherwise secured together alongtheir longitudinal edges 2, and also along longitudinal parallel lines 3to form eight tubular elements 4.

To maintain the elements in an open condition suitable framing orspacers can be inserted into each element. This framing is convenientlyin the form of four longitudinal metal member 5 intermediate the ends ofthe elements, arranged and held in equidistant peripheral location by anumber of transverse frame elements 6 secured thereto. These frameelements are conveniently of diamond shape whereby the framing willimpart a diamond shape to the section of each element. The ends of eachelement are conveniently closed by mean of nylon lacing or otherrot-proof material threaded through lacing holes 7 formed in the upperand lower sheets of the element adjacent the ends thereof. The holes 7,which may also serve for joining the ends of elements together bylacing, are conveniently reinforced by means of nylon webbing stitchedor otherwise secured along the upper and lower edges of the ends of theelements, and through which the said holes, which may be eyeleted, areformed.

To enable two or more mattress units to be joined together side by side,similar lacing holes 9 may be provided along each side of each unit, thereinforcing nylon webbing being indicated by reference 10.

Each element is provided with a meshed upper panel 8, that is, the panelportion which will normally face upwardly, the gauge of the mesh beingsuch as to permit the particular grade of ballast employed to passtherethrough into the interior of the element, the mesh convenientlybeing about inch square or /2 inch square.

If the mattress is to be sunk in water at the chosen location it can befloated into position above the location and the ballast is poured orprojected onto the upper surface of the mattress so that it will passthrough the mesh of the upper panel into the interior of the elements,and finally sink the mattress to the required submerged position.Further ballast may, if desired, be deposited on the upper surface ofthe mattress, to be retained in the corrugations formed by the diamondsection of the elements.

In a modified construction, the underface of the elements are formedwith meshed panels 8a, the mesh being such that when the mattress islaid on the surface of the channel bed the bed material, such as sand,will tend to penetrate or percolate through the mesh of the underfaceinto the interior of the compartment. The mesh of the underface is ofsuch size that while allowing the ingress of sand or other bed materialinto the element, it will not allow the egress of the ballast with whichthe mattress wa originally weighted.

The ballast employed may be a mix of wet sand with a small percentage,say 2 or 3 percent, of lime mixed cold with about 20 percent hot bitumenfiuxed with a small amount of coal tar (creosote) brought to about 300F. The proportions of the mix will vary with the type and grading of thesand available at the particular site at which the mix is to be used,and with the type of bitumen used.

Whilst it is preferred to use a mix as above described, other forms ofballast may be employed, such, for example, as sand or gravel alone,depending upon the hydraulic or other conditions existing at the site.

To retain a mattress in location, varying amounts of the ballast will beused in and on top of the mattress according to the hydraulicconditions, e.g. tides and currents and nature of the bed or surface onwhich the mattress is finally located. However, as a general example,the amount of mix or other ballast supplied before immersion to thefloating mattress to effect immersion, is conveniently such as toimpart, when the mattress is immersed, from about 3 pounds to 20 poundper square foot of negative buoyancy.

Each mattress is conveniently about 15 feet along the length of theelements and about 15 feet wide. The mattress units can be joined end toend and side to side in a convenient manner by passing lacing of nylonthrough adjoining end lacing hole of the elements and through adjoiningside lacing holes, and the units thus joined can be passed or floatedinto the water into the required position.

Although reference has been made to floating the mattresses intoposition and then sinking them, it or they can be positioned directly onlocations where these are not submerged at certain times, such as at lowtide, or in the construction or reinforcing of river banks above normalwater level.

Although a diamond shaped cross-section has been mentioned for theelements 4, the framing 5 and 6 may be formed to impart to the elementsother cross-sections, such as circular, elliptical or triangular.

Referring now to FIGS. 4 and 5 of the drawings, the element according tothis second embodiment is in the form of a mattress constructed from anupper sheet 11 and a lower sheet 12, both of rot-proof material such asa polyester fibre. The upper sheet 11 is in the form of a mesh ofsquare, diamond, triangular, elliptical or circular pattern and of suchsize that ballast which is to be used to weght the finished mattressonto the bed of the water flow channel and material contained insuspension by the water will pass through it and into the mattress. Thesheet 12 may be a closely woven or impervious sheet, or in amodification to be described later it may be a fine mesh material. Thetwo sheets 11 and 12 are sewn, thermally welded or otherwise fastenedtogether along their longitudinal edges, of which one edge 13 is shownin FIG. 5.

They are also sewn or otherwise fastened together along lines,respectively 14, 15, 16 etc., which are parallel to the edge 13 so as toform a series of tubular sections which each have an upper wall composedof the wide mesh material and a lower wall which is of the imperviousclosely woven or finely meshed material. The mesh of the material of theupper walls of the tubular sections is such that ballast of a size whichis to be used will pass through the mesh, while the material of thelower walls will retain the ballast within the mattress. The tubularsections are of such diameter that a number of distending members 17 mayeasily be pushed into each of the tubular sections in order to keep thetubular sections distended. The members 17 may be round, oval or of anyother convenient shape and they preferably contain regular or irregularcavities 18. One possible form is a sphere made of a synthetic plasticsmaterial having a number of cavities 18 which are of irregular shape andthe cavity may be between one-quarter of a square inch and one squareinch in area. If desired the distending member 17 may be filled withconcrete or other heavy material so that the members 17 will assist insinking the element when it is placed in the water. Each of the members17 has a hole through its centre and a wire 19 is passed through theholes in the line of members in each tube. The wire may consist of asolid or multistrand metal cable which has a thick covering of asynthetic plastics material extruded over it. In order to separate themembers 17 by a desired distance spacers 20 of appropriate length areplaced over the wires 19. The spacers 20 may, for example, be shortlengths of half-inch bore synthetic garden hose.

After each of the tubular cavities has been filled with a desired numberof the members 17 and spacers 20 the ends of the wires 19 may be securedeither at the outer ends of the two end members 17, or the wires may becontinued as shown in FIG. 4 and incorporated in a joint indicated at 21at which the two sheets 11 and 12 are secured together. Provision forsecuring the ends of the sheets together may be made by fixing eyeletsalong the end edges of the two sheets, and if desired reinforcingwebbing may be sewn or otherwise secured to the end edges of the sheetsto strengthen them in order to form a firm anchorage for the eyelets. Arot-proof cord, for example nylon cord, may be used to lace up the endsof the sheets to close the sections.

The longitudinal edges 13 may also be provided with strengthening websand eyelets so that adjacent mattresses may be laced together to form alarge composite mattress covering any desired areas. The eyelets at theends of the mattresses may also be used to lace mattresses together endto end.

The individual mattresses may, of course, be completely prefabricatedand they only require to be laced together on site if two or more are tobe used together to cover a large area. After the mattresses have beensunk ballast is poured into the water so that it falls on to themattress or mattresses and passes through the mesh of the upper sheet 11into the inside of the mattress. It will readily be understood thatbecause of the presence of the distending members 17 the ballast willfall into the tubular sections bet-ween the distending members, whichhelp to retain the ballast. Once in position in the mattress, theballast and waterborne material which has entered the mattress, will notbe readily dislodged by powerful under-currents so that the mattressretains its shape and remains in position indefinitely.

In a modification the lower sheet 12 is also made of a meshed materialbut of much finer mesh size than the upper sheet 11, so that the bedmaterial, such as sand, may enter the mattress thereby helping it tosettle down on the bed on which it has been placed but is notsufficiently large to enable the ballast which has entered the mattressto escape.

The ballast employed, or alternative forms thereof, and the manner inwhich it is used may be substantially the same as that already describedwith reference to FIGS. 1 to 3. The size of the mattresses may be thesame as previously mentioned and may be floated into position or placeddirectly in a nonsubmerged position as already explained.

I claim:

1. Means for minimizing scouring action in water flow channelscomprising a tubular element of rot-proof flexible material having ameshed upper panel through which ballast can be passed to the interiorof the element, a meshed lower panel, the size of the mesh of said lowerpanel being such that sand or other bed material from the water channelmay pass into the element but ballast which has entered through theupper panel cannot escape through said lower panel.

2. Means as claimed in claim 1, wherein said tubular element is providedinternally with a plurality of spaced apart distending members ofspherical, ovoid or other shape, the surfaces of which are formed withirregular cavities.

3. Means as claimed in claim 2 wherein the distending members in theelement are threaded on a wire with tubular spacing pieces between saidmembers, the latter being partially or fully filled with concrete orother heavy material so that they will assist in causing the element tosink when it is released.

4. Means as claimed in claim 1 including supporting framing so arrangedto maintain the element in open position.

5. Means as claimed in claim 1 including a number of elements joinedtogether in parallel relationship to form a mattress unit.

6. Means as claimed in claim 4 in which the supporting framingcomprises, in each element, four longitudinal metal members extendingintermediate the ends of the elements, arranged and held in equidistantperipheral location by a number of transverse framing elements securedthereto.

7. Means as claimed in claim 1 including comprising lacing holes in theupper and lower panels of each element adjacent the ends thereof, toenable the element to be closed.

8. Means as claimed in claim 7 including reinforcing webbing stitched orotherwise secured along the upper and lower edges of the element or eachelement, through which the lacing holes are formed.

9. Means as claimed in claim 1 comprising reinforcing webbing along eachside of the element or unit, lacing holes being formed in thereinforcing webbing to enable elements or units to be joined together.

References Cited UNITED STATES PATENTS 752,781 2/1904 Kerr 61-34 984,1212/1911 Condie 61-38 1,060,357 4/1913 Nies 61-3 2,092,183 9/1937 Rehfeld61-38 3,423,228 2/ 1969 Lamberton 61-38 PETER M. CAUN, Primary ExaminerU.S. C1. X.R.

